package helper

import (
	"fmt"
	"time"
)

func GetMonday(ts time.Time) time.Time {
	if ts.Weekday() != time.Monday {
		if ts.Weekday() == time.Sunday {
			return ts.AddDate(0, 0, -6)
		} else {
			return ts.AddDate(0, 0, -int(ts.Weekday()-1))
		}
	}
	return ts
}

func IsWeekend(ts time.Time) bool {
	return ts.Weekday() == time.Saturday || ts.Weekday() == time.Sunday
}

func GetKW(t time.Time) int {
	_, kw := t.ISOWeek()
	return kw
}

func FormatDuration(d time.Duration) string {
	return FormatDurationFill(d, false)
}

// Converts duration to string
func FormatDurationFill(d time.Duration, fill bool) string {
	hours := int(d.Abs().Hours())
	minutes := int(d.Abs().Minutes()) % 60
	sign := ""
	if d < 0 {
		sign = "-"
	}
	switch {
	case hours > 0 && minutes == 0:
		return fmt.Sprintf("%s%dh", sign, hours)
	case hours > 0:
		return fmt.Sprintf("%s%dh %dmin", sign, hours, minutes)
	case minutes > 0:
		return fmt.Sprintf("%s%dmin", sign, minutes)
	default:
		if fill {
			return "0min"
		}
		return ""
	}
}

func IsSameDate(a, b time.Time) bool {
	return a.Truncate(24 * time.Hour).Equal(b.Truncate(24 * time.Hour))
}

func GetWorkingDays(startDate, endDate time.Time) int {
	if endDate.Before(startDate) {
		return 0
	}
	var count int = 0
	for d := startDate.Truncate(24 * time.Hour); !d.After(endDate); d = d.Add(24 * time.Hour) {
		if !IsWeekend(d) {
			count++
		}
	}
	return count
}

func FormatGermanDayOfWeek(t time.Time) string {
	return days[t.Weekday()][:2]
}

var days = [...]string{
	"Sonntag", "Montag", "Dienstag", "Mittwoch", "Donnerstag", "Freitag", "Samstag"}